In connection with the technical background, reference is made, besides German Patent Publication DE 29 47 521 A1, in particular to German Patent Publication DE 34 44 586 A1.
In connection with the employment of air-cooled turbine blades, in particular in gas turbines, the cooling air supply for these turbine blades via channels in the turbine rotating disks which terminate in the disk grooves, has basically proven itself. In this manner it is also possible to supply cooling air to a second turbine rotating disk arranged behind a first rotating disk, in that a portion of the air flow reaching the disk grooves of the first rotating disk is moved via these disk grooves towards the back, so to speak, into the space between the first and second rotating disk. To this end it is possible to provide appropriate passages in the so-called closure plates, which secure the blades inserted into the disk grooves.
The conveyance of a sufficiently large cooling air flow into the respective disk groove can be problematical, if a portion of this cooling air flow is also intended for cooling a downstream turbine rotating disk. It is not possible to design the cross-sectional surface of a cooling air channel terminating in the groove bottom of the disk groove to have any arbitrary size, since in this outlet area the spatial regions of the individual stress concentrations of the peripheral stress are superimposed on each other and can cause locally greatly increased stress levels which are undesirable.